clayton3854

i know i have open diff front and rear and i wanna lock them at some point. but right now i wanna fully understand what open differential means? i hear it means when 1 tire is off the ground thats the one that spins? and is there a closed differential since there is an open one? or is closed mean your locked? thanks guys

gpXJ

Closed would be like a limited slip or posi-lock, from my understanding. Some of the rear 8.25 diffs in XJ's came with limited slip. I want to say if you have ABS and an 8.25, then it would have limited slip.

winston427

The 8.25 was never equipped with ABS, only the Dana 35 had that option.

The way an open diff works is power is supplied to the wheel with the least traction. Which is why the tire off the ground will spin instead of the one that has traction.

The term closed diff is something you will almost never hear. It is either referred to as limited slip (LSD) or locked. Limited slip is not a true locker as it is designed to allow the wheel to slip as needed. It is still better than an open diff but not as good as a true locker.

SeriousOffroad

4.3L XJ

The term "open" comes from the fact that that when you have a stock differential you can see through the center of it. Typically when you get a locker, spool or positrac you can no longer do this because of different mechanical parts there. But you are correct in that with tow open differentials you can raise opposite corners off the ground and go nowhere. Locking a differential will effectively make one axle shaft out of two so the wheels will have to turn the same speed, unless something breaks.